<!DOCTYPE html>  
<html lang="zh">  
<head>  
    <meta charset="UTF-8">  
    <meta name="viewport" content="width=device-width, initial-scale=1.0">  
    <title>框架集示例</title>  
</head>  
<frameset rows="20%,75%,5%" frameborder="1">  
    <frame name="top" src="header.html" noresize>  
    <frameset cols="25%,75%">  
        <frame name="left" src="left.html" noresize>  
        <frame name="content" src="content.html" noresize>  
    </frameset>  
    <frame name="foot" src="footer.html" noresize>  
</frameset>  
<noframes>  
    <body>  
        <p>此页面需要浏览器支持框架功能。</p>  
    </body>  
</noframes>  
</html>  